It was 40 years ago, the Boyer River was home to a rich and diverse aquatic life. Local residents could swim and fish there. Smelt rainbow sky had spawn near the mouth. He laid its eggs on clean gravel from the bottom of the riverbed. The smelt fishing was popular in the river before being banned in 1977. Since then, agriculture has flourished in this small watershed. Although urban and industrial pressures remained weak, the changes to the environment by agriculture have deeply disturbed the balance of aquatic ecosystems. Today basin water courses suffer from excessive intake of nutrients and silted. They no longer home to flora or fauna remarkable but instead are subject to eutrophication problems. The smelt, pike, eel, like ten other fish species have now deserted during the Boyer River. Local residents it will bathe more. The waters of the aquifer is related to those of the river, diffuse pollution threatens drinking water. Faced with the reality of this rapid degradation, local stakeholders with the support of relevant departments combined their efforts within the Action Group for the Restoration of Boyer (GIRB). Since 1992, they have undertaken the river restoration and raising awareness on changing agricultural practices. Very close to Quebec, this small basin is subject to special monitoring. Its flow and changes in its water quality is automatically measured and high frequency. Hope that her study teaches us about the mistakes not to reproduce!